Container base



FIG. 1 is a perspective view of my design comprising a container base;

FIG. 2 is a back view;

FIG. 3 is a front view;

FIG. 4 is a left side view;

FIG. 5 is a right side view;

FIG. 6 is a top view; and,

FIG. 7 is a bottom view.

The dashed lines in FIGS. 1–6 represent environmental structure and form no part of the claimed design. All other surface(s) or portion(s) of the embodiments of my design not shown in the figures or otherwise described in the specification form no part of the claimed design. 

The ornamental design for a container base, as shown and described. 